It won't be optimum to do it this way and won't get the ultimate best sound, but at whatever crossover frequexy you choose just insert a capacitor in series with each speaker of a value that rolls the response off at the crossover frequency.

What/who are you replying to here?

Tube Radio wrote:

If the Fisher has a tape loop you can connect the record out jacks to right after the volume control then where the volume control originally connected you can connect the tape in jacks. Then all you need is an OP-AMP buffer between the record out and plate amp. The plate amp will then serve as the crossover.

My strong preference is to not modify the source unit in any way. This keeps them interchangeable. I would also much prefer, other than for the bass reinforcement, for the audio chain to remain tube based.

Last edited by Sol on Oct Sun 29, 2017 5:50 pm, edited 1 time in total.

I've heard a lot of good things about Magnepans over the years. Nowadays you generally get the small ones with the built in subwoofer. I've heard those, was not impressed, especially for the price. I wouldn't mind hearing the big ones though.

In fact, 30-35 watts is about the limit/sweet spot for an individual amplifier, any larger and the inductance of the larger output transformers start rolling off the high end, make the transformers smaller and they begin to saturate at low frequencies. the size of transformers you need for a 30 watt push-pull amp more-or-less splits the difference. Want more, bridge multiple amplifiers together, don't make a single bigger amp.

Interesting. I wonder how many others agree with this?

Brett_Buck wrote:

The solution that no one has mentioned (perhaps because it is obvious, but I have mastered statements of the obvious) - I would look at the heritage Klipsch systems, Cornwall, Heresy, etc, on up to the Klipschorns if you have an appropriate room. They were designed precisely for this purpose, acceptable volume levels with the tube amps of the 50's and 60's. You can get old ones, or have them made to order new. The only others that I would seriously consider are Bozaks, all the way up to the Concert Grand.

I actually did mention Klipschorns in the OP, and would very much like to talk about those and other vintage speakers like the Bozaks. Perhaps in a couple days when I have more time.

Brett_Buck wrote:

Don't worry about damage, if they can build a new one, they can supply repair parts. I used to have some version of the Heresy to use with the various wimpy SET amps people wanted me to build them, I never had a failure of any time (of the speakers, anyway...) and I would play them for 24-48 hours straight for burn-in purposes many times. It was fine even with 2A3s, in fact, I preferred the 2A3 amplifiers (at something around 3 watts) over the 300B (at around 8 watts) in most cases.

I always worry about damage, and of course that's one of the draws of vintage speakers - that they are vintage. Once they have replacement drivers in them, are they really 'vintage'? And that's the concern, that somebody's going to expect modern performance from a 2A3 SET and play trap or dubstep. How's that going to work out? Really, this exercise is about getting the most out of old equipment, of using old equipment where it shines and how to make it relevant to modern listening. Defining a 'perfect speaker' I thought would be good starting point.

Brett_Buck wrote:

Having said all that, however, I have excellent results with a Val Alstine Ultimate 70 (measured at 33 watts) with my B&W 803S (91 db/watt). Anything at 90 or above would be adequate for most purposes in my relatively small room. It plays Virgil Fox records *just fine* and effects in superhero movies and "Band of Brothers" are stunningly powerful, sounds like the house is going to come down. The only limitation is that the very lowest organ tones start getting muddy compared to my prime system, which is a hybrid with 850-900 watts/channel (only extrapolated that one, never had the guts to run it at that level for long enough, those resistors were glowing red). The extra power and much lower output impedance seem to force as much current into it as the speakers want.

My listening space is about 40,000 cubic feet, so you can see why I have questions about the bass issue.

I like SLS 2-way Planar Ribbon Drivers with conical woofers in the same enclosure. SLS is now owned by Dolby Labs and they no longer are in the home speaker market. However, you can find used home theater speakers and systems.

The proper buckets can be purchased from Firehouse Subs for $2.00 each.

Quite possibly your best bet will be to build some bucket subs which are crossed over at 70Hz then get some Bozaks or other vintage speaker that have a listed bass response down to 70Hz then you won't need to mod anything and you will get great sound.

The reason you don't want the sub and main speakers reproducing some of the same frequencies because those frequencies will sound louder than the rest. That said if using a regular sub it is possible to set the crossover to just under where the mains roll off.

I myself use one bucket sub in my vintage stereo system and it does great paired with a 20 WPC Lafayette amp and a pair of KLH 22A speakers.

I designed a speaker with 99 db efficiency down to about 80 Hz. To match that with the subwoofer driver I picked out will require a subwoofer amp of about 500 watts for a matching output down to about 25 Hz.

The subwoofer driver is an 18 inch unit. I want to build it all into one speaker, so essentially it will be one big bass reinforced speaker.

In fact, 30-35 watts is about the limit/sweet spot for an individual amplifier, any larger and the inductance of the larger output transformers start rolling off the high end, make the transformers smaller and they begin to saturate at low frequencies. the size of transformers you need for a 30 watt push-pull amp more-or-less splits the difference. Want more, bridge multiple amplifiers together, don't make a single bigger amp.

Interesting. I wonder how many others agree with this?

Presumably anyone who has done enough circuit analysis, but I long since learned to not spend a lot of time arguing about the topic.

Quote:

Brett_Buck wrote:

The solution that no one has mentioned (perhaps because it is obvious, but I have mastered statements of the obvious) - I would look at the heritage Klipsch systems, Cornwall, Heresy, etc, on up to the Klipschorns if you have an appropriate room. They were designed precisely for this purpose, acceptable volume levels with the tube amps of the 50's and 60's. You can get old ones, or have them made to order new. The only others that I would seriously consider are Bozaks, all the way up to the Concert Grand.

I actually did mention Klipschorns in the OP, and would very much like to talk about those and other vintage speakers like the Bozaks. Perhaps in a couple days when I have more time.

<< snip >>

My listening space is about 40,000 cubic feet, so you can see why I have questions about the bass issue.

Assuming we are talking about conventional hi-fi, for that size room, I wouldn't think tube amplification is a good idea, but if you must, bridge two ~35 watt amplifiers and use Klipschorns. That's why they exist. For that, I think that you would be unhappy with even Concert Grands regardless of the power you use, and those are the obvious alternatives for giant ancient tube amp speakers.

It sounds like the worst possible application for a tube amp. I would use about 500 watts/channel conventional amps and maybe something like B&W 801s (any vintage, I would pick Nautilus 801s or 801Ds) or even 808s. Or, last time I checked, VTL was still in business, you will get your power (and the limitations that come with it) and then use regular speakers.

I think the other obvious issue with rooms this large is bass resonant effects, you probably want to add bass traps in the corners, at least, and maybe around the crown of the room, too. It's probably more important to get the room right than what speakers you use, but once you get the room tamed, it will be a lot deader, meaning more power will be required.

For this size room (with an 8 foot ceiling, far larger than the average family home), you have to consider tweeter dispersion as well, and that's where vintage speakers are so limited. It also completely eliminates any sort of planar speaker, with their laser-beam dispersion pattern. If the room has high ceiling with multiple levels, you have to consider vertical as well as horizontal dispersion. The seems to demand a speaker with free-air tweeters, again, not something you find before about 1980.

This is a difficult problem (read "difficult" as "expensive") and will require an unconventional or extreme solution.

For PA or sound reinforcement, it's a lot less demanding and some of these erzatz and less expensive options are worth looking, including relatively inexpensive subwoofers.

...This is a difficult problem (read "difficult" as "expensive") and will require an unconventional or extreme solution...

Thank you for your lengthy reply, however I seem to have misrepresented the issue. Let's go back a bit.

Sol wrote:

...Really, this exercise is about getting the most out of old equipment, of using old equipment where it shines and how to make it relevant to modern listening. Defining a 'perfect speaker' I thought would be good starting point...

I think we got off track when I started talking about my situation rather than the topic. Yes, I have a large test space - my shop space, actually. I only thought it relevant in that if I could at least minimalize the issues inherent in my test space, then we might have a solution that could be adopted to many other situations.

Right now, as I said earlier, I have built a test speaker that is somewhat adequate to the job. It is an 8 cubic foot cabinet with a single 15 inch bass speaker, and features a removable top baffle and external crossover so that I might test multiple drivers in multiple configurations. Currently I am using a 6.5 inch mid and a horn tweeter, and it has an overall sensitivity of about 93 db. It works 'adequately' with the 30 watt Fisher - though I have to keep a fan on the Fisher when played at volume for too long. There is of course no headroom, and I didn't actually brace it that well, since it's really just a test speaker, but as I said, version 2 is in the works. Generally I use a 160 watt modern SS amp to run it. I think another 6 db efficiency could make quite a difference.

So THAT is why I'd really like to talk about the older speakers, and what they did right and what they did wrong. It is an exercise in nostalgia as well as modern understanding and technology. My hope is to put them together at some point.

For example, I was told an Altec A7 is a very nice vintage speaker, however it gives hardly any output below 50 Hz or above 10Khz. Interesting, yes?

So THAT is why I'd really like to talk about the older speakers, and what they did right and what they did wrong. It is an exercise in nostalgia as well as modern understanding and technology. My hope is to put them together at some point.

OK, but what you need for any specific situation is highly dependent on the environment and the application (high fidelity 2-channel, surround, PA, sound reinforcement, etc). Essentially any of the speakers we are talking about from this era would fare *very poorly* by modern standards in an objective sense, so it boils down to the room and the application to decide which limitations you have to care about, and which advantages you can take advantage of.

I have seen people running 2 1/2 watts/channel into B&W 601s with excellent results in a 8x10' room, and I have also seen people with 1.2 kW/channel using Bozak Concert Grands* in similar rooms that were absolutely horrific, and people with Klipshorns spaced about 5 feet apart that sounded like someone was kicking a 55 gallon oil drum. You want to hear a tympani, not stick your head inside it.

Brett

*and yes, I know what you are thinking, and it wasn't too long before it happened. It was horrible with nonetheless astonishing dynamics at 1/4 watt RMS , but if you want to show off, it's really hard to keep your hand off the volume knob.

OK, but what you need for any specific situation is highly dependent on the environment and the application (high fidelity 2-channel, surround, PA, sound reinforcement, etc). Essentially any of the speakers we are talking about from this era would fare *very poorly* by modern standards in an objective sense, so it boils down to the room and the application to decide which limitations you have to care about, and which advantages you can take advantage of.

The primary issue is bass response. The room is important because it will influence speaker placement and to some extent response compensation for resonances and suck-out. Speaker placement is not an issue, as long as there is some flexibility. Bass response can largely be compensated for using the onboard DSP in the sub plate amp. The one issue I need to address is that sub CAPACITY is adequate when needed, if needed. So I agree, there are concerns, which I am trying to address.

Brett_Buck wrote:

I have seen people running 2 1/2 watts/channel into B&W 601s with excellent results in a 8x10' room, and I have also seen people with 1.2 kW/channel using Bozak Concert Grands* in similar rooms that were absolutely horrific, and people with Klipshorns spaced about 5 feet apart that sounded like someone was kicking a 55 gallon oil drum. You want to hear a tympani, not stick your head inside it

Point taken.

Brett_Buck wrote:

*and yes, I know what you are thinking, and it wasn't too long before it happened. It was horrible with nonetheless astonishing dynamics at 1/4 watt RMS , but if you want to show off, it's really hard to keep your hand off the volume knob.

Again, it's a question of CAPACITY, which in my book translates directly to headroom. Yes, sometimes I like it loud - but wouldn't it be nice to know your system isn't running out of gas anytime soon when listened to at reasonable levels?

As I said in the OP, there is no 'perfect' speaker - but I hoped for something with some flexibility, at least.

The primary issue is bass response. The room is important because it will influence speaker placement and to some extent response compensation for resonances and suck-out. Speaker placement is not an issue, as long as there is some flexibility. Bass response can largely be compensated for using the onboard DSP in the sub plate amp. The one issue I need to address is that sub CAPACITY is adequate when needed, if needed. So I agree, there are concerns, which I am trying to address.

"onboard DSP in the sub plate amp"? I don't think I know what that means. I guess you are talking about some digital signal processing in some sort of powered subwoofer? I take it that this is for some sort of a surround sound system or sound reinforcement, then, rather than a 2-channel hifi system? I will defer to others on that one.

"onboard DSP in the sub plate amp"? I don't think I know what that means. I guess you are talking about some digital signal processing in some sort of powered subwoofer? I take it that this is for some sort of a surround sound system or sound reinforcement, then, rather than a 2-channel hifi system? I will defer to others on that one.

High-tech sound reinforcing technology is readily available today, and that's one of the points of this thread, that back in the day bass wasn't very well understood. The other point is the desirability of the 'vintage sound'. Again, my aim is to put those together somehow.

And actually, my initial aim is simply mono. I am trying to isolate the speaker on it's own merits, though with typical vintage hi-fi tube amps in mind.

From another post above:

Sol wrote:

Sol wrote:

I designed a speaker with 99 db efficiency down to about 80 Hz. To match that with the subwoofer driver I picked out will require a subwoofer amp of about 500 watts for a matching output down to about 25 Hz.

The subwoofer driver is an 18 inch unit. I want to build it all into one speaker, so essentially it will be one big bass reinforced speaker.

And you seem to know something about it. Again, do appreciate your input.

Vintage hi-fi speakers have been my thing for 20+ years. Having been lucky enough to own almost all of the best, I would recommend Altec- Lansing.The most successful of the consumer models would be the systems that employ the 500 cycle horn and 2 15" woofers with a 500 cycle crossover.look up the Heathkit Legato lowboy and the Altec Laguna, these are the 2 best in my opinion.The lower xover point and larger horn offer an advantage over the 800 cycle Altec systems and 1200 cycle JBL systems.The A-7 or "Magnificent" in consumer trim with 1 15" in a horn cabinet is also excellent.If wanting to save and build your own out of parts, the 1" compression drivers recommended are 802B-D, 15" woofers 803A/B/416 for bass reflex. 515 really for horn loading. Altec crossovers were mostly 12db, 2nd order.Klipsch can be good, but they used cheap parts in most cases which just don't compare imo.I also like the Jensen Imperial 3-way horn speaker.You'll get pretty good 40-50 cycle low end with the altec systems in your room, can always augment the extreme LFwith a variety of modern subs.Good luck.

my radio interest turned into an audio interest and i've been active in both hobbies since i was a kid. i've owned my lions share of quality speakers and have to say i have reached my happy place.

Altec A5 voice of the theaters with the 515 woofers and big horns up top. they are not the most accurate, they arent small, and they arent light. they are the most fun to listen to speakers i have ever heard. jazz sounds like a band hanging out in my mancave, rock sounds like you're at the concert. you just want to listen to more music on these and thats what matters, enjoyment.

they are also VERY efficient. a 6v6 SE amp is actually useful and enough for most of my listening. a crown 30wpc amp and your rockin.